The rapid development of social economy leads to the rapid growth of the quantity of autos in China and thus the frequent occurrence of road traffic accidents, which have become one of the important factors affecting the sense of public safety in China in recent years. The traffic safety has become one of the basic issues affecting social harmony and improvement of people's livelihood. China urgently needs to improve traffic safety in terms of technology, policy, education, etc. Among them, the improvement of vehicle safety design is an important part.
Technologies for improving vehicle safety are mainly divided into passive safety technologies and active safety technologies. Passive safety technologies are used to protect people and articles inside and outside a vehicle in an accident. Active safety technologies are used to prevent and reduce vehicle accidents and to prevent people from being harmed. Active safety technologies are the key and trend in the development of modern vehicle safety technologies.
It has become a new way for countries to try to solve road traffic safety problems by using advanced wireless communication technologies and a new generation of information processing technologies on the basis of a communication collision warning system to implement real-time information exchange between vehicles and between vehicles and roadside infrastructure, inform each other of the current status (including position, speed, acceleration and driving path of the vehicle) and the known road environment information, cooperatively acquire road hazard conditions, and provide collision warning information in time to prevent road traffic safety accidents.
Vehicle-to-Everything (V2X) refers to providing vehicle information through sensors, on-board terminals and electronic tags mounted on vehicles, implementing Vehicle-to-Vehicle (V2V), Vehicle-to-Pedestrian (V2P) and Vehicle-to-Infrastructure (V2I) intercommunications using various communication technologies, and effectively using information by way of extraction, sharing, etc. and effectively controlling and providing comprehensive services for vehicles by use of an information network platform. FIG. 1 is a schematic diagram of sending traffic and scheduling information to a vehicle through a network information platform in the related art.
In recent years, with the development of new mobile communication technologies, the Long Time Evolution (LTE) technology starts to be used in the world to solve problems in the research on application of V2X communication.
A Roadside Unit (RSU) has a function of gateway of receiving requests from a vehicle and ensuring the access of the vehicle to the Internet, as well as functions of data operation, storage and forwarding.
Vehicle-to-Roadside-Unit (V2R) is also referred to as V2I. The main features of V2R communication are described below.
(1) When an RSU broadcasts, broadcast messages are sent only to vehicles within the coverage area of the RSU.
(2) Single-hop transmission between an RSU and a vehicle prevents the adverse effects such as low packet transfer success rate and low network throughput caused by multi-hop.
(3) An RSU can quickly receive detected passing vehicles, traffic lights and some traffic information, and can process, reorder and select such information before sending the information to a vehicle.
The above three aspects ensure that a vehicle passing by an RSU is connected to the RSU so as to reliably accesses the Internet or download data stored in the RSU in real time.
FIG. 2 is a schematic diagram of Device-to-Device (D2D) communication in 3GPP in the related art. As shown in FIG. 2, D2D user plane data is sent through an air interface PC5 between UEs and not through an Evolved Packet Core (EPC), while D2D control plane signaling passes through the EPC. D2D communication includes a scenario where a UE is within an LTE coverage area and a scenario where a UE is outside an LTE coverage area. D2D includes discovery and communication. A UE participating in D2D may schedule resources through an eNB or select resources from a resource pool to send data. D2D communication data is sent four times, i.e., the same data is sent four times. Incremental Redundancy (IR) provides reliability to a receiving UE merging data sent four times.
D2D communication includes resource scheduling SA and service data transmission. Resource scheduling specifies configuration of resources for of service data, and is sent twice. D2D discovery or communication uses LTE Physical Uplink Shared Channel (PUSCH) resources and a Single-carrier Frequency-Division Multiple Access approach.
In the process of researching and practicing the D2D technology in the related art, the following problems occur: the D2D technology is applicable to a low-speed scenario with a small number of UEs, so resource scheduling information and service data are sent separately, where scheduling information is sent twice and communication data is sent four times. However, in LTE V2X, the D2D technology in the related art cannot meet the requirements of a high-speed scenario with a large number of UEs.